CN217902022U

CN217902022U - Laser radar receiving system

Info

Publication number: CN217902022U
Application number: CN202220371712.4U
Authority: CN
Inventors: 王剑波; 孙康; 武光杰; 杜晨光
Original assignee: Lorenz Ningbo Technology Co ltd
Current assignee: Lorenz Ningbo Technology Co ltd
Priority date: 2022-02-23
Filing date: 2022-02-23
Publication date: 2022-11-25
Anticipated expiration: 2032-02-23

Abstract

The utility model provides a laser radar receiving system relates to laser radar technical field, can make the problem design of the SNR degradation of received signal for solving current laser radar receiving system. The laser radar receiving system comprises a positive lens group, a negative cylindrical lens and a photoelectric detector which are arranged in sequence, wherein the positive lens group is configured to focus signal light returned by a target object; the plane of the negative cylindrical lens faces the positive lens group, the concave surface of the negative cylindrical lens faces the photoelectric detector, and the negative cylindrical lens is configured to receive the light focused by the positive lens group; the photodetector is configured to receive light exiting through the negative cylindrical lens. The utility model discloses can reduce the adverse effect that ambient light noise brought, improve received signal's SNR.

Description

Laser radar receiving system

Technical Field

The utility model relates to a laser radar technical field particularly, relates to a laser radar receiving system.

Background

The laser radar mainly comprises a transmitting system, a receiving system and an information processing system, wherein the transmitting system is used for transmitting laser signals to a target object; the receiving system is used for receiving the laser signal transmitted on the target object; the information processing system is used for processing the received laser signals. In the receiving system, since the receiving aperture of the photodetector is much smaller than the optical receiving aperture of the receiving system, after the receiving system receives the signal light reflected by the target object, the light beam compression is performed to adapt to the receiving aperture of the photodetector.

However, due to the existing lidar, most are not circularly symmetric in the field of view of transmission, i.e.: the divergence angles of the laser light emitted from the transmission system in the horizontal direction and the vertical direction are not uniform, which results in the following problems when the conventional reception system is used for laser signal reception: the dimension with the smaller divergence angle will have more ambient background light entering the photodetector, thus degrading the signal-to-noise ratio of the received signal.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a laser radar receiving system to solve the technical problem that current laser radar receiving system can make the SNR degradation of received signal.

The utility model provides a laser radar receiving system, including positive lens group, negative cylindrical lens and the photoelectric detector who sets gradually, wherein, positive lens group is configured to focus the signal light that returns by the target object; the plane of the negative cylindrical lens faces the positive lens group, the concave surface of the negative cylindrical lens faces the photoelectric detector, and the negative cylindrical lens is configured to receive the light focused by the positive lens group; the photodetector is configured to receive the light exiting through the negative cylindrical lens.

Furthermore, the positive lens group comprises n positive lenses and m negative lenses, wherein n is more than or equal to 1, and m is more than or equal to 0.

Further, the positive lens group comprises a positive lens and a negative lens, wherein the positive lens is a meniscus positive lens, and the negative lens is a biconcave negative lens.

Further, the positive lens group further includes a diaphragm, and the positive lens, the diaphragm and the negative lens are sequentially arranged along an optical path direction of the signal light returned by the target object, wherein the diaphragm has a light through hole located in a middle portion thereof, and the light through hole is configured to receive the light focused by the positive lens.

Furthermore, the light through hole is a circular hole, and the diameter of the circular hole is 2-4 mm; and/or the distance from the diaphragm to the negative lens is L1, and the value range of L1 is 0.2-4 mm.

Further, the surfaces of the lenses in the positive lens group and the negative cylindrical lens are each provided with an antireflection film.

Further, the photodetector is any one of an APD (Avalanche Photo Diode), a PIN (P-type semiconductor-impurity-N-type semiconductor), an MPPC (multi-pixel Photon counter), a SPAD (Single Photon Avalanche Diode), and a SiPM (Silicon photomultiplier).

Further, the distance from the photodetector to the negative cylindrical lens is L2, where L2 is 1% to 20% of the focal length of the positive lens group.

Further, the refractive index of the lens in the positive lens group and the refractive index of the negative cylindrical lens are both between 1.3 and 1.7.

Further, the side surface of a lens in the positive lens group is a frosted surface, and the side surface is a non-light-passing surface of the corresponding lens.

The utility model discloses beneficial effect that laser radar receiving system brought is:

by arranging the laser radar receiving system mainly composed of the positive lens group, the negative cylindrical lens and the photoelectric detector, when the laser radar receiving system is used, signal light returned by a target object is focused through the positive lens group, then the focused light is emitted by the plane of the negative cylindrical lens, is further emitted through the concave surface of the negative cylindrical lens, and is finally received by the photoelectric detector. The arrangement of the negative cylindrical lens enables the light emitted by the negative cylindrical lens to have different view fields in the horizontal direction and the vertical direction, namely, the arrangement of the negative cylindrical lens enables the view angles in the two dimension directions in the horizontal direction and the vertical direction to be different on the photoelectric detector with the same size, the view angle in the direction of adding the negative cylindrical lens is specifically reduced, and the inconsistency of the receiving view fields in the horizontal direction and the vertical direction is realized.

In summary, the laser radar receiving system can obtain different view fields in the horizontal direction and the vertical direction, so that when receiving optical signals which are emitted by the emission view field and have inconsistent divergence angles in the horizontal direction and the vertical direction, background light in the environment is reduced or even avoided from entering the photoelectric detector, adverse effects caused by ambient light noise are effectively reduced, and the signal-to-noise ratio of the received signals is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic diagram of a receiving horizontal field of view of a laser radar receiving system according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a receiving vertical field of view of a laser radar receiving system according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a laser radar receiving system provided with a diaphragm according to an embodiment of the present invention;

fig. 4 is a schematic shape diagram of a lens of a laser radar receiving system according to an embodiment of the present invention.

Description of reference numerals:

100-positive lens group; 200-negative cylindrical lens; 300-a photodetector; 400-diaphragm; 500-signal light;

110-positive meniscus lens; 120-biconcave negative lens;

410-clear aperture.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Fig. 1 is a schematic diagram illustrating a principle view of a receiving horizontal field of view of the lidar receiving system provided in this embodiment, and fig. 2 is a schematic diagram illustrating a principle view of a receiving vertical field of view of the lidar receiving system provided in this embodiment. As shown in fig. 1 and 2, the present embodiment provides a laser radar receiving system including a positive lens group 100, a negative cylindrical lens 200, and a photodetector 300, which are arranged in this order, wherein the positive lens group 100 is configured to focus a signal light 500 returned by a target object; the plane of the negative cylindrical lens 200 faces the positive lens group 100, the concave surface of the negative cylindrical lens 200 faces the photodetector 300, and the negative cylindrical lens 200 is configured to receive the light focused by the positive lens group 100; the photodetector 300 is configured to receive the light exiting through the negative cylindrical lens 200.

When the laser radar receiving system is used, signal light 500 returned by a target object is focused by the positive lens group 100, and then the focused light enters from the plane of the negative cylindrical lens 200, further exits from the concave surface of the negative cylindrical lens 200, and is finally received by the photoelectric detector 300. The negative cylindrical lens 200 is arranged, so that the light emitted through the negative cylindrical lens 200 has different viewing fields in the horizontal direction and the vertical direction, that is, by arranging the negative cylindrical lens 200, the viewing angles in the two dimensional directions in the horizontal direction and the vertical direction are different on the photoelectric detector 300 with the same size, specifically, the viewing angle in the direction of adding the negative cylindrical lens 200 is reduced, and the inconsistency of the receiving viewing fields in the horizontal direction and the vertical direction is realized.

In summary, the laser radar receiving system can obtain different view fields in the horizontal direction and the vertical direction, so that when receiving optical signals with inconsistent divergence angles in the horizontal direction and the vertical direction, which are emitted by the emission view field, background light in the environment is reduced or even avoided from entering the photoelectric detector 300, adverse effects caused by ambient light noise are effectively reduced, and the signal-to-noise ratio of the received signals is improved.

In this embodiment, the positive lens group 100 may include n positive lenses and m negative lenses, where n is greater than or equal to 1 and m is greater than or equal to 0. With this arrangement, the focusing effect on the signal light 500 can be ensured.

Preferably, the positive lens group 100 includes one piece of positive lens and one piece of negative lens, that is, n =1,m =1, specifically, the positive lens is a meniscus type positive lens 110, and the negative lens is a biconcave type negative lens 120.

By arranging the positive lens group 100 in a form of combining a meniscus positive lens 110 and a biconcave negative lens 120, the number of lenses used can be effectively reduced while the signal light 500 is reliably focused, so that the cost is saved, and the assembly is facilitated.

Referring to fig. 1 and fig. 2, in the present embodiment, the curvatures of the two concave surfaces of the negative biconcave lens 120 are different. In other embodiments, the two concave curvatures of the biconcave negative lens 120 may also be set to be the same.

Fig. 3 is a schematic structural diagram of the lidar receiving system provided in this embodiment when an aperture 400 is provided. With reference to fig. 1 and fig. 2 and fig. 3, in this embodiment, the positive lens group 100 may further include an aperture 400, and specifically, the positive lens, the aperture 400 and the negative lens are sequentially disposed along an optical path direction of the signal light 500 returned by the object, where the aperture 400 has a light passing hole 410 located in a middle portion thereof, and the light passing hole 410 is configured to receive the light focused by the positive lens.

By arranging the diaphragm 400 between the positive lens and the negative lens, the light beam focused by the positive lens can be limited to a certain extent, so that the aim of limiting the field of view is fulfilled, and the signal light 500 can be reliably received by the photoelectric detector 300.

In this embodiment, the direction indicated by the arrow S in fig. 1 and 2 is the optical path direction of the signal light 500 returned from the target object.

It should be noted that the middle of the diaphragm 400 is not the absolute center of the diaphragm 400, that is, as long as there are entities around the light-passing hole 410 of the diaphragm 400, the position of the light-passing hole 410 can be regarded as the middle of the diaphragm 400.

Specifically, in the present embodiment, the light passing hole 410 is a circular hole, and the diameter of the circular hole is 2 to 4mm. Wherein the diameter of the circular hole comprises two end values of 2mm and 4mm.

Referring to fig. 3, in the present embodiment, the distance from the diaphragm 400 to the negative lens is L1, and the value range of L1 is 0.2-4 mm. Wherein the value of L1 comprises two endpoint values of 0.2mm and 4mm.

Specifically, in the present embodiment, the surfaces of the lenses in the positive lens group 100 and the surface of the negative cylindrical lens 200 are each provided with an antireflection film. That is, the surfaces of the meniscus positive lens 110, the biconcave negative lens 120, and the negative cylindrical lens 200 are all provided with the antireflection film.

By providing the anti-reflection film on the surfaces of the meniscus positive lens 110, the biconcave negative lens 120, and the negative cylindrical lens 200, the receiving efficiency of the signal light 500 can be effectively improved.

Specifically, in the present embodiment, the photodetector 300 is any one of APD, PIN, MPPC, SPAD, and SiPM. The photoelectric detector 300 with the arrangement mode has the advantages of reliable detection and higher sensitivity.

Referring to fig. 3, in the present embodiment, a distance between the photodetector 300 and the negative cylindrical lens 200 is L2, wherein L2 is 1% to 20% of a focal length of the positive lens assembly 100. That is, in the present embodiment, the photodetector 300 is located away from the focal point in the generatrix direction of the negative cylindrical lens 200, and the length of defocus is 1% to 20% of the focal length of the positive lens group 100.

With this arrangement, the energy of the signal light 500 can be enhanced when it exits to the photodetector 300.

In the present embodiment, the refractive index of the lenses in the positive lens group 100 and the refractive index of the negative cylindrical lens 200 are both 1.5. That is, the refractive indexes of the meniscus positive lens 110, the biconcave negative lens 120, and the negative cylindrical lens 200 are all 1.3 to 1.7.

Through this setting, can improve the transmissivity of signal light 500 to improve the operational reliability of this embodiment lidar receiving system.

Preferably, the refractive index of all of the meniscus positive lens 110, the biconcave negative lens 120, and the negative cylindrical lens 200 is 1.5.

In this embodiment, the side surfaces of the lenses in the positive lens group 100 are frosted surfaces, and the side surfaces are non-light-passing surfaces of the corresponding lenses. That is, the sides of the meniscus positive lens 110 and the biconcave negative lens 120 are frosted surfaces.

By such arrangement, the signal light 500 can be prevented from being emitted from the side surfaces of the meniscus positive lens 110 and the biconcave negative lens 120, and the influence of stray light on the photoelectric detector 300 in the laser radar receiving system of the embodiment is reduced.

Fig. 4 is a schematic shape diagram of a lens of the lidar receiving system according to this embodiment. As shown in fig. 4, the meniscus positive lens 110, the biconcave negative lens 120, and the negative cylindrical lens 200 may be circular or square. When the lens optic is circular on the left side of fig. 4, a flat surface can be machined into the side of the optic. Wherein the height of the plane is 0.5-8 mm, including two end points of 0.5mm and 8mm.

In this embodiment, the diameters of the meniscus positive lens 110 and the biconcave negative lens 120 may be the same or may not be the same.

Specifically, when the diameters of the two are consistent, the part which does not pass light and the edge thereof are subjected to sanding treatment, the optimal value of the mesh number of the grinding wheel used in the treatment process is between 250 and 400 meshes, including two end values of 250 meshes and 400 meshes, and a layer of extinction ink is smeared on the frosted surface of the grinding wheel, so that the adverse effect of stray light on the photoelectric detector 300 in the laser radar receiving system of the embodiment is further reduced; when the diameters of the two are not consistent, the diameter of the biconcave negative lens 120 is reduced as much as possible, the optimal value of the diameter of the biconcave negative lens 120 is to add 0.5-2 mm (including two end points of 0.5mm and 2 mm) on the basis of the light transmission aperture of the actually used photoelectric detector 300, and the edge of the biconcave negative lens 120 is sanded.

In addition, in this embodiment, the light-passing aperture of the photodetector 300 is 0.2 to 2mm, the receiving focal length of the positive lens group 100 composed of the meniscus positive lens 110 and the biconcave negative lens 120 is 700 to 200mm, the optimal focal length of the meniscus positive lens 110 is 12 to 18mm, the optimal focal length of the biconcave negative lens 120 is-2 to-5 mm, and the optimal focal length of the negative cylindrical lens 200 is-5 to-10 mm. The value ranges include two endpoints.

As a specific example of this embodiment, the glass material of the meniscus positive lens 110 is H-ZF71A, the focal length is 15.678mm, the on-axis thickness D1 is 3.02mm, the glass material of the biconcave negative lens 120 is H-ZF71A, the focal length is-3.437 mm, the on-axis thickness D2 is 2.02mm, the glass material of the negative cylindrical lens 200 is H-ZF71A, the focal length is-7.805 mm, and the on-axis thickness D3 is 1.98mm.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention, and the scope of the present invention is defined by the appended claims.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising one of 8230; \8230;" 8230; "does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

In the above embodiments, the descriptions of the orientations such as "upper", "lower", "side", and the like are based on the drawings.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser radar reception system, characterized by comprising a positive lens group (100), a negative cylindrical lens (200), and a photodetector (300) arranged in this order, wherein the positive lens group (100) is configured to focus signal light (500) returned by a target; the plane of the negative cylindrical lens (200) faces the positive lens group (100), the concave surface of the negative cylindrical lens (200) faces the photodetector (300), and the negative cylindrical lens (200) is configured to receive the light focused by the positive lens group (100); the photodetector (300) is configured to receive light exiting through the negative cylindrical lens (200).

2. The lidar receiving system of claim 1, wherein the positive lens group (100) comprises n positive lenses and m negative lenses, wherein n ≧ 1, m ≧ 0.

3. The lidar receiving system of claim 2, wherein the positive lens group (100) comprises a positive lens and a negative lens, wherein the positive lens is a positive meniscus lens (110) and the negative lens is a negative biconcave lens (120).

4. The lidar receiving system according to claim 3, wherein the positive lens group (100) further comprises a diaphragm (400), and the positive lens, the diaphragm (400) and the negative lens are sequentially arranged along an optical path direction of the signal light (500) returned by the target, wherein the diaphragm (400) has a light passing hole (410) located at a middle portion thereof, and the light passing hole (410) is configured to receive the light focused by the positive lens.

5. The lidar receiving system according to claim 4, wherein the light passing hole (410) is a circular hole having a diameter of 2-4 mm; and/or the distance from the diaphragm (400) to the negative lens is L1, and the value range of L1 is 0.2-4 mm.

6. The lidar receiving system according to claim 1, wherein a surface of a lens in the positive lens group (100) and a surface of the negative cylindrical lens (200) are each provided with an antireflection film.

7. The lidar receiving system of claim 1, wherein the photodetector (300) is any one of an APD, PIN, MPPC, SPAD, and SiPM.

8. The lidar receiving system of claim 1, wherein a distance from the photodetector (300) to the negative cylindrical lens (200) is L2, wherein L2 is 1% to 20% of a focal length of the positive lens group (100).

9. The lidar receiving system of claim 1, wherein a refractive index of a lens in the positive lens group (100) and a refractive index of the negative cylindrical lens (200) are each between 1.3 and 1.7.

10. The lidar receiving system of claim 1, wherein a side surface of a lens in the positive lens group (100) is a frosted surface, and the side surface is a non-light-passing surface of the corresponding lens.